State, Society and Political Institutions in Revolutionary Ethiopia

Summary Ethiopia's experiment with the Leninist model is best seen as a means of forging the state into a centralised and disciplined structure of political control rather than as an attempt to apply socialist solutions to the intractable problems facing African states. Ethiopia's leaders have largely succeeded in this effort, in contrast to most other allegedly ‘revolutionary’ African regimes, and the resulting state is not a personalised power structure as are so many others in the Third World. Some notable achievements have followed in Ethiopia. Highly effective structures of rural and urban government have been built. An equitable system of landholding has been established, education has been expanded and literacy has risen sharply. But Ethiopia's centralised state has also been a source of failure. It has not had an adequate answer to regional diversity. Nor has a centrally directed economy revived an ailing economy — indeed, it has done damage, especially in the agricultural sector. The fragile economic base appears incapable of sustaining the huge state apparatus that has been erected. The central problem, then, in Ethiopia — unlike most of sub?Saharan Africa — is not to create an effective structure of power, but to make creative use of it. Résumé L'Etat, la Société et les Institutions Politiques dans l'Ethiopie Révolutionare L'expérimentation de l'Ethiopie avec le modèle Léniniste est considérée au mieux comme moyen d'établir une structure étatique centralisée et disciplinée de contrôle politique plutôt que comme moyen d'appliquer des solutions socialistes aux problèmes insolubles auxquels font face les pays d'Afrique. Les dirigeants éthiopiens ont largement réussi dans ce sens, contrastant avec la plupart des autres régimes africains soit?disant ‘révolutionaires’, et le résultat n'est pas une structure de pouvoir personalisé comme c'est le cas pour beaucoup d'autres pays du tiers monde. Des résultats remarquables ont suivi en Ethiopie. Des structures très efficaces de gouvernement rural et urbain ont été instaurées. Un système équitable de propriété des terres a été établi, l'éducation et le degré d'alphabétisation ont beaucoup augmenté. Mais l'état centralisé éthiopien a aussi échoué dans d'autres domaines. Il n'a pas eu de réponses adéquates en ce qui concerne la diversité régionale. L'économie centralisée n'a pas non plus su relancer une économie souffrante — en fait, elle a causé des dommages, particulièrement dans le secteur agricole. La base économique fragile semble être incapable de soutenir l'appareil énorme de l'état qui a été construit. Le problème principal, donc en éthiopie — au contraire de la plupart des pays de l'Afrique sub?Saharienne — n'est pas de créer une structure de pouvoir efficace, mais d'en faire une utilisation créative. Resumen Estado, Sociedad e Instituciones Políticas en la Etiopía Revolucionaria El experimento de Etiopía con el modelo feminista es considerado más como un medio de forjar el estado en una estructura de control político centralizada y disciplinada, que como un intento a aplicar soluciones socialistas a los problemas intratables que enfrentan los estados africanos. Los líderes de Etiopía han tenido bastante éxito en este empeño, contrastando con muchos otros regímenes africanos Ilamados ‘revolucionarios’, y el estado resultante no es un estado con una estructura personal con poder, como muchas otras existentes en el Tercer Mundo. Han obtenido resultados memorables en Etiopía. Han construídos estructuras rurales y urbanas gubernamentales altamente satisfactorias. Han establecido un sistema equitativo de propiedad de tierras, y la educación y el alfabetismo han crecido con rapidez. Pero el estado centralizado de Etiopía también ha tenido sus fallos. No ha producido una solución adecuada a la diversidad regional Tampoco la economía centralizada ha renovado una economía enfermiza — de hecho, la ha dañado, especialmente en el sector agrícola. La frágil base económica existente parece incapaz de sostener la enorme maquinaria estatal construida. El problema central en Etiopía — en contraste con la mayoría de los países del sub?Sahara — no es por lo tanto el crear una estructura de poder eficaz, sino el hacer uso de ella creativamente

Hanna Rubinkowska: Ethiopia on the Verge of Modernity: the Transfer of Power during Zewditu’s Reign 1916–1930

Review  

A New Approach to High Reliability UHF Controllers

Many available UHF antenna positioners lack reliability for high-intensity commercial use. Similarly, many UHF antenna controllers lack appropriate interfaces for remote and automated control. We present a number of ways to simplify UHF ground station design and improve reliability. We also describe an improved antenna controller we have designed, with Ethernet connectivity, human- and machine-friendly interfaces, detailed metrics for fault diagnosis, and an improved control algorithm designed to minimise gearbox stresses and improve pointing accuracy

Functional reconstitution of the mitochondrial Ca2+/H+ antiporter Letm1

The leucine zipper, EF hand–containing transmembrane protein 1 (Letm1) gene encodes a mitochondrial inner membrane protein, whose depletion severely perturbs mitochondrial Ca2+ and K+ homeostasis. Here we expressed, purified, and reconstituted human Letm1 protein in liposomes. Using Ca2+ fluorophore and 45Ca2+-based assays, we demonstrate directly that Letm1 is a Ca2+ transporter, with apparent affinities of cations in the sequence of Ca2+ ≈ Mn2+ > Gd3+ ≈ La3+ > Sr2+ >> Ba2+, Mg2+, K+, Na+. Kinetic analysis yields a Letm1 turnover rate of 2 Ca2+/s and a Km of ∼25 µM. Further experiments show that Letm1 mediates electroneutral 1 Ca2+/2 H+ antiport. Letm1 is insensitive to ruthenium red, an inhibitor of the mitochondrial calcium uniporter, and CGP-37157, an inhibitor of the mitochondrial Na+/Ca2+ exchanger. Functional properties of Letm1 described here are remarkably similar to those of the H+-dependent Ca2+ transport mechanism identified in intact mitochondria

Simultaneous knockout of Slo3 and CatSper1 abolishes all alkalization- and voltage-activated current in mouse spermatozoa

During passage through the female reproductive tract, mammalian sperm undergo a maturation process termed capacitation that renders sperm competent to produce fertilization. Capacitation involves a sequence of changes in biochemical and electrical properties, the onset of a hyperactivated swimming behavior, and development of the ability to undergo successful fusion and penetration with an egg. In mouse sperm, the development of hyperactivated motility is dependent on cytosolic alkalization that then results in an increase in cytosolic Ca2+. The elevation of Ca2+ is thought to be primarily driven by the concerted interplay of two alkalization-activated currents, a K+ current (KSPER) composed of pore-forming subunits encoded by the Kcnu1 gene (also termed Slo3) and a Ca2+ current arising from a family of CATSPER subunits. After deletion of any of four CATSPER subunit genes (CATSPER1–4), the major remaining current in mouse sperm is alkalization-activated KSPER current. After genetic deletion of the Slo3 gene, KSPER current is abolished, but there remains a small voltage-activated K+ current hypothesized to reflect monovalent flux through CATSPER. Here, we address two questions. First, does the residual outward K+ current present in the Slo3 −/− sperm arise from CATSPER? Second, can any additional membrane K+ currents be detected in mouse sperm by patch-clamp methods other than CATSPER and KSPER? Here, using mice bred to lack both SLO3 and CATSPER1 subunits, we show conclusively that the voltage-activated outward current present in Slo3 −/− sperm is abolished when CATSPER is also deleted. Any leak currents that may play a role in setting the resting membrane potential in noncapacitated sperm are likely smaller than the pipette leak current and thus cannot be resolved within the limitation of the patch-clamp technique. Together, KSPER and CATSPER appear to be the sole ion channels present in mouse sperm that regulate membrane potential and Ca2+ influx in response to alkalization

Interactions between β Subunits of the KCNMB Family and Slo3: β4 Selectively Modulates Slo3 Expression and Function

The pH and voltage-regulated Slo3 K(+) channel, a homologue of the Ca(2+)- and voltage-regulated Slo1 K(+) channel, is thought to be primarily expressed in sperm, but the properties of Slo3 studied in heterologous systems differ somewhat from the native sperm KSper pH-regulated current. There is the possibility that critical partners that regulate Slo3 function remain unidentified. The extensive amino acid identity between Slo3 and Slo1 suggests that auxiliary beta subunits regulating Slo1 channels might coassemble with and modulate Slo3 channels. Four distinct beta subunits composing the KCNMB family are known to regulate the function and expression of Slo1 Channels.To examine the ability of the KCNMB family of auxiliary beta subunits to regulate Slo3 function, we co-expressed Slo3 and each beta subunit in heterologous expression systems and investigated the functional consequences by electrophysiological and biochemical analyses. The beta4 subunit produced an 8-10 fold enhancement of Slo3 current expression in Xenopus oocytes and a similar enhancement of Slo3 surface expression as monitored by YFP-tagged Slo3 or biotin labeled Slo3. Neither beta1, beta2, nor beta3 mimicked the ability of beta4 to increase surface expression, although biochemical tests suggested that all four beta subunits are competent to coassemble with Slo3. Fluorescence microscopy from beta4 KO mice, in which an eGFP tag replaced the deleted exon, revealed that beta4 gene promoter is active in spermatocytes. Furthermore, quantitative RT-PCR demonstrated that beta4 and Slo3 exhibit comparable mRNA abundance in both testes and sperm.These results argue that, for native mouse Slo3 channels, the beta4 subunit must be considered as a potential interaction partner and, furthermore, that KCNMB subunits may have functions unrelated to regulation of the Slo1 alpha subunit

Role of the C-terminal domain in the structure and function of tetrameric sodium channels.

Voltage-gated sodium channels have essential roles in electrical signalling. Prokaryotic sodium channels are tetramers consisting of transmembrane (TM) voltage-sensing and pore domains, and a cytoplasmic carboxy-terminal domain. Previous crystal structures of bacterial sodium channels revealed the nature of their TM domains but not their C-terminal domains (CTDs). Here, using electron paramagnetic resonance (EPR) spectroscopy combined with molecular dynamics, we show that the CTD of the NavMs channel from Magnetococcus marinus includes a flexible region linking the TM domains to a four-helix coiled-coil bundle. A 2.9 Å resolution crystal structure of the NavMs pore indicates the position of the CTD, which is consistent with the EPR-derived structure. Functional analyses demonstrate that the coiled-coil domain couples inactivation with channel opening, and is enabled by negatively charged residues in the linker region. A mechanism for gating is proposed based on the structure, whereby splaying of the bottom of the pore is possible without requiring unravelling of the coiled-coil

Role of the C-terminal domain in the structure and function of tetrameric sodium channels

Voltage-gated sodium channels have essential roles in electrical signalling. Prokaryotic sodium channels are tetramers consisting of transmembrane (TM) voltage-sensing and pore domains, and a cytoplasmic carboxy-terminal domain. Previous crystal structures of bacterial sodium channels revealed the nature of their TM domains but not their C-terminal domains (CTDs). Here, using electron paramagnetic resonance (EPR) spectroscopy combined with molecular dynamics, we show that the CTD of the NavMs channel from Magnetococcus marinus includes a flexible region linking the TM domains to a four-helix coiled-coil bundle. A 2.9 Å resolution crystal structure of the NavMs pore indicates the position of the CTD, which is consistent with the EPR-derived structure. Functional analyses demonstrate that the coiled-coil domain couples inactivation with channel opening, and is enabled by negatively charged residues in the linker region. A mechanism for gating is proposed based on the structure, whereby splaying of the bottom of the pore is possible without requiring unravelling of the coiled-coil

EPRDF's Revolutionary Democracy and Religious Plurality: Islam and Christianity in post-Derg Ethiopia

In 1991 the Ethiopian Peoples’ Revolutionary Democratic Front (EPRDF) introduced policies aimed at recognizing the country’s long-standing religious diversity, providing a public arena for religious groups, and maintaining a sharp division between religion and the state. This further roded the traditionally dominant position of the Ethiopian Orthodox Church, strengthened Protestant Christian and Muslim communities, and created a more flux and competitive configuration among the religious communities. Seeking to maintain its political power, the EPRDF has at the same time made efforts to monitor and control the different religious communities. Therefore, the last 20 years have been marked by uneven developments, in which the government’s accommodating attitudes have been interlaced with efforts to curtail the influence of the religious communities. This article surveys the intersection and reciprocal influences between EPRDF policies and religious communities over the last 20 years, and discusses how Muslims and Christians (Orthodox and Protestant) have negotiated their roles in relation to politics and public life. These developments have, the article argues, led to the emergence of divergent and competing narratives, reconfiguring self-understanding, political aspirations and views of the religious other. The EPRDF ideology of ‘‘revolutionary democracy’’ has, in this sense, enabled religion to surface as a force for social mobilization and as a point of reference for attempting to define nationhood in Ethiopia

A Homozygous Mutation in the Tight-Junction Protein JAM3 Causes Hemorrhagic Destruction of the Brain, Subependymal Calcification, and Congenital Cataracts

The tight junction, or zonula occludens, is a specialized cell-cell junction that regulates epithelial and endothelial permeability, and it is an essential component of the blood-brain barrier in the cerebrovascular endothelium. In addition to functioning as a diffusion barrier, tight junctions are also involved in signal transduction. In this study, we identified a homozygous mutation in the tight-junction protein gene JAM3 in a large consanguineous family from the United Arab Emirates. Some members of this family had a rare autosomal-recessive syndrome characterized by severe hemorrhagic destruction of the brain, subependymal calcification, and congenital cataracts. Their clinical presentation overlaps with some reported cases of pseudo-TORCH syndrome as well as with cases involving mutations in occludin, another component of the tight-junction complex. However, massive intracranial hemorrhage distinguishes these patients from others. Homozygosity mapping identified the disease locus in this family on chromosome 11q25 with a maximum multipoint LOD score of 6.15. Sequence analysis of genes in the candidate interval uncovered a mutation in the canonical splice-donor site of intron 5 of JAM3. RT-PCR analysis of a patient lymphoblast cell line confirmed abnormal splicing, leading to a frameshift mutation with early termination. JAM3 is known to be present in vascular endothelium, although its roles in cerebral vasculature have not been implicated. Our results suggest that JAM3 is essential for maintaining the integrity of the cerebrovascular endothelium as well as for normal lens development in humans